The proposed training program is the centerpiece in efforts to provide postdoctoral training in laboratory genetics for medical geneticists at Harvard Medical School (HMS). This program has made possible the opportunity to offer training to physicians and scientists in a wide variety of disciplines, enabling them to take advantage of the extraordinarily rich academic environment offered at HMS and its affiliated institutions as well as the greater Boston scientific community. In addition, it has served to promote interactions between investigators and provided a forum for increasing faculty contact with trainees in didactic sessions. The training laboratories of the program have historically been centered at HMS and its affiliated institutions including Brigham and Women's Hospital (BWH), the HMS Department of Genetics, Beth Israel Deaconess Medical Center (BIDMC), Children's Hospital Boston (CHB), Dana Farber Cancer Institute (DFCI), and Massachusetts General Hospital (MGH), and more recently have also included laboratories at the Massachusetts Institute of Technology (MIT). Shortly before the last renewal of this training grant, the Harvard Medical School-Partners HealthCare Center for Genetics and Genomics (HPCGG) was initiated. One of the HPCGG's goals is to facilitate training of the next generation of medical geneticists and the HMS Training Grant in Genetics is an integral component in accomplishing this goal. Most recently, the creation of the Broad Institute of MIT and Harvard has even further enhanced training opportunities for geneticists in Boston. The focus of this training is medical and human genetics, and the program is fully integrated with the HMS American Board of Medical Genetics (ABMG) training program, which is accredited by the ABMG in all areas of training (Clinical Genetics, Ph.D. Medical Genetics, Biochemical Genetics, Cytogenetics, and Molecular Genetics), providing the opportunity for trainees to become active candidates for the certification examination in a discipline(s) of medical genetics in addition to receiving laboratory training for two to three years. Since the last renewal of this T32, we have successfully implemented combined residency training programs in Internal Medicine and Medical Genetics and in Pediatrics and Medical Genetics in addition to subspecialty training in Molecular Genetic Pathology.